package cn.imokay;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Vector;
import java.util.concurrent.ConcurrentHashMap;

public class Main {
    public static void main(String[] args) {
        Vector<String> strings = new Vector<>();

        Hashtable<Object, Object> objectObjectHashtable = new Hashtable<>();
        objectObjectHashtable.put(0,0);

        ConcurrentHashMap<Object, Object> objectObjectConcurrentHashMap = new ConcurrentHashMap<>();
        objectObjectConcurrentHashMap.put(0,0);

        HashMap<Object, Object> objectObjectHashMap = new HashMap<>();

        objectObjectHashMap.put(0,0);
        System.out.println("Hello world!");

        HashSet<String> strings1 = new HashSet<>();
        strings1.add("");
        Object[] array = strings1.toArray();


        ThreadLocal<Object> objectThreadLocal = new ThreadLocal<>();
        Object o = objectThreadLocal.get();
    }
}